324 MOBPHOLOGY AND EVOLUTION
Apes. But the actual Tarsioids which gave rise to both Platyrrhini and Catarrhini have not yet been discovered. This is one of the most serious gaps in the geological record.
The remains of the Adapidae have been found in the Eocene formations of France and Switzerland. They belong to three species: A dap is magnus, A. priscus and A. parisiensis. The skull agrees with that of the Notharctidae in its general form, and in the communication between the orbit and temporal fossa under a post-orbital bar. The orbit is small, with a prominent lip-like ring, and the upper orifice of the naso-lachrymal duct is within the cavity. The sagittal crest is well marked and the zygoma is strong. The ramus of the mandible is large, the coronoid process is high up and recurved; and the glenoid cavity is such that it only permits the mandible to move in a hinge-like manner as in the Carnivora. The tympanic region is as in the Lemurs, and the cranial cavity is large. The teeth are not as specialized as in the modern Lemurs. It can be shown, from a study of all osseous fragments hitherto discovered, that the Adapidae are intermediate between the Notharctidse and the modern Lemurs to which they gave rise.
In Madagascar extinct Lemurs belonging to other Families have been discovered. Some, such as Neso-pithecus, have a monkey-like appearance, and the discoverer, Forsyth Major, wondered whether that fossil was the highest Lemuroid or the lowest Ape. There is, however, no doubt that it is a Lemur, for the skull and skeleton provide very definite proof.
Of the extinct Lemuroidea, Megaladapis insignis,